Delta Competitor is a term used to refer to two major airlines in the UNITED States: UNITED Airlines and Trans World Airlines (TWA). UNITED Airlines, founded in 1926, is one of the oldest airlines in the world and is the largest airline in the UNITED States. TWA, founded in 1930, was the first airline to offer coast-to-coast service in the UNITED States. Both airlines have been major competitors of Delta Airlines since their founding.